In hospitals and laboratories, several chemical and diagnostic analyses are done by automatic analyzing equipment. The level of automation varies, but the present trend is to streamline the analyzing work as much as possible. As many more complicated analyzes must be done by highly educated laboratory personnel involving a lot of manual work, the productivity and throughput of a laboratory and individual analyzers has been low. If the automation rate is increased, more of the work can be performed automatically inside the automatic system without involvement of highly skilled personnel. Ideally, laboratory assistants simply load samples in racks into the analyzing apparatuses and laboratory chemists and biologists may concentrate on interpretation of the results and managing the operation of the laboratory. Such a system provides a good throughput combined with high certainty and quality of the work.
In order to enable the high rate of automation, many automated features are needed. One of the features is reliable management of sample liquids, reagents and other fluids needed for the operation of the analyzer. This involves sample vessels, reagent vessels and reaction vessels and means for transferring them within the automated analyzer. Another particularly important feature when the automated analyzer handles sensitive samples and/or utilizes volatile reagents is the use of a capped reaction vessel. However, capped reaction vessels introduce an additional mechanical problem when used on-board automated instrumentation: they must be automatically opened and closed. The following patent documents disclose some of the typical systems currently used in the art.
U.S. Pat. No. 6,589,789 shows an apparatus with two grippers, one for standard test tubes and one for the container that holds them. In here two grippers are needed, which evidently makes the apparatus complicated and expensive. U.S. Pat. No. 5,775,755 has a gripper that is used for transferring standard test tubes. Herein the test tubes are grabbed from above with four jaws that have a coated surface that provides sufficient friction to hold the tubes when they are lifted from a rack and moved. The gripper is tailored for test tubes.